Installing directory poetry package with dependencies in secondary source fails

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• MacOS 10.14:
• 1.0.0b8:

Issue

Due to https://github.com/pypa/pip/issues/7444 installing a directory which is managed by poetry or has a pyproject.toml file present will cause the --no-deps argument to be ignored.

This can go unnoticed as long as you are only working with pypi dependencies but when your package depends on a private pypi repository this causes installs to fail.

[wakemaster39]

Ok many many hours later I have sorted out the behaviour of PEP 517 and PEP 518 and what its going on here causing the problem.

I don’t know the full implications, but here is the issue

https://github.com/sdispater/poetry/blob/e943a4e127b0a658e76386006c60b79954a8fa57/poetry/masonry/api.py#L21-L29

And here is the snippet from pip

        # Install any extra build dependencies that the backend requests.
        # This must be done in a second pass, as the pyproject.toml
        # dependencies must be installed before we can call the backend.
        with self.req.build_env:
            runner = runner_with_spinner_message(
                "Getting requirements to build wheel"
            )
            backend = self.req.pep517_backend
            with backend.subprocess_runner(runner):
                reqs = backend.get_requires_for_build_wheel()

        conflicting, missing = self.req.build_env.check_requirements(reqs)
        if conflicting:
            _raise_conflicts("the backend dependencies", conflicting)
        self.req.build_env.install_requirements(
            finder, missing, 'normal',
            "Installing backend dependencies"
        )

Basically at this point, pip has gone into the build isolation and poetry has been retrieved and installed. pip then queries poetry and asks “what else is required for me to build this wheel”. To which poetry is responding with the dependencies of the package.

I do not know enough about packaging, but I think returning all the dependencies is a mistake. The build system doesn’t need my dependencies to package up my wheel, I only need it to use the wheel.

I have been able to test this out hacking at pip to be the following:

            with backend.subprocess_runner(runner):
                reqs = backend.get_requires_for_build_wheel()
                reqs = []

By doing this none of my dependencies are installed and the wheel is generated and installed the way I expect.

I don’t know how this impact C extensions or if those are even supported with poetry right now but I think that get_requires_for_build_wheel(config_settings=None) should be modified to return an empty list. That is all that is required to build the wheel, poetry and nothing else.

[wakemaster39]

Looks good now to me as its the same hack I have been running for a month now.

Thanks for providing a proper fix for it. I will close our my old hacky PR.